1 files changed, 108 insertions, 0 deletions
diff --git a/stack-alloc.c b/stack-alloc.c
new file mode 100644
index 000000000..d9619f622
--- /dev/null
+++ b/stack-alloc.c
@@ -0,0 +1,108 @@
+/* Stack allocation routines.  This is intended for machines without support
+   for the `alloca' function.
+
+Copyright (C) 1996 Free Software Foundation, Inc.
+
+This file is part of the GNU MP Library.
+
+The GNU MP Library is free software; you can redistribute it and/or modify
+it under the terms of the GNU Library General Public License as published by
+the Free Software Foundation; either version 2 of the License, or (at your
+option) any later version.
+
+The GNU MP Library is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
+License for more details.
+
+You should have received a copy of the GNU Library General Public License
+along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
+the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+MA 02111-1307, USA. */
+
+#include "stack-alloc.h"
+
+typedef struct tmp_stack tmp_stack;
+
+void *malloc ();
+static unsigned long max_total_allocation = 0;
+static unsigned long current_total_allocation = 0;
+
+static tmp_stack xxx = {&xxx, &xxx, 0};
+static tmp_stack *current = &xxx;
+
+/* Allocate a block of exactly <size> bytes.  This should only be called
+   through the TMP_ALLOC macro, which takes care of rounding/alignment.  */
+void *
+__tmp_alloc (size)
+     unsigned long size;
+{
+  void *this;
+
+  if (size > (char *) current->end - (char *) current->alloc_point)
+    {
+      void *chunk;
+      tmp_stack *header;
+      unsigned long chunk_size;
+      unsigned long now;
+
+      /* Allocate a chunk that makes the total current allocation somewhat
+	 larger than the maximum allocation ever.  If size is very large, we
+	 allocate that much.  */
+
+      now = current_total_allocation + size;
+      if (now > max_total_allocation)
+	{
+	  /* We need more temporary memory than ever before.  Increase
+	     for future needs.  */
+	  now = now * 3 / 2;
+	  chunk_size = now - current_total_allocation + sizeof (tmp_stack);
+	  current_total_allocation = now;
+	  max_total_allocation = current_total_allocation;
+	}
+      else
+	{
+	  chunk_size = max_total_allocation - current_total_allocation + sizeof (tmp_stack);
+	  current_total_allocation = max_total_allocation;
+	}
+
+      chunk = malloc (chunk_size);
+      header = chunk;
+      header->end = (char *) chunk + chunk_size;
+      header->alloc_point = (char *) chunk + sizeof (tmp_stack);
+      header->prev = current;
+      current = header;
+    }
+
+  this = current->alloc_point;
+  current->alloc_point = (char *) this + size;
+  return this;
+}
+
+/* Typically called at function entry.  <mark> is assigned so that __tmp_free
+   can later be used to reclaim all subsecuently allocated storage.  */
+void
+__tmp_mark (mark)
+     tmp_marker *mark;
+{
+  mark->which_chunk = current;
+  mark->alloc_point = current->alloc_point;
+}
+
+/* Free everything allocated since <mark> was assigned by __tmp_mark */
+void
+__tmp_free (mark)
+     tmp_marker *mark;
+{
+  while (mark->which_chunk != current)
+    {
+      tmp_stack *tmp;
+
+      tmp = current;
+      current = tmp->prev;
+      current_total_allocation -= (((char *) (tmp->end) - (char *) tmp)
+				   - sizeof (tmp_stack));
+      free (tmp);
+    }
+  current->alloc_point = mark->alloc_point;
+}